ML20236P036
| ML20236P036 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 11/09/1987 |
| From: | Papanic G YANKEE ATOMIC ELECTRIC CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| FYR-87-117, NUDOCS 8711170117 | |
| Download: ML20236P036 (2) | |
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Talephone (017) 872-8100 i
TWX 710-380 7619 IYANKEE ATOMIC ELECTRIC COMPANY l
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1671 Worcester Road, Framingham, Massachusetts 01701 w
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. November 9,.1987 FYR'87-117 United' States Nuclear Regulatory Commission 4
Document' Control Desk l
-Washington, DC 20555 i
References:
(a) License No. DPR-3-(Docket No. 50-29)
(b)
Letter,.W. C. Coppersmith (CE) to Combustion Engineering I
Fuel User's Group, " Fuel Pellet Diameter Deviations," REL 87-070, dated-September 18, 1987
Subject:
Potential Fuel' Pellet Tolerance Deviation
Dear Sir:
1 Yankee was informed by Combustion Engineering Inc. (CE), in-Reference (b) that the fuel pellet diameter design tolerance.may not have been maintained for Yankee Nuclear Power Station (YNPS)-Cycle 18 and Cycle 19-3
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reload fuel. While we'are not sure if this is'the actual case for Yankee, we have evaluated the effect of the larger tolerance on YNPS's performance as follows:
4 A.'
Fuel Mechanical Analyses l
The Fuel Mechanical Analyses were evaluated for the fuel pellet j
diameter tolerance variation by CE.
The analyses utilized NRC-approved methodology and showed that margin exists to design criteria for all fuel mechanical design features.
B.
Nuclear Design Analyses The fuel pellet diameter tolerance variations do not have a significant impact on the nuclear design.
Specifically, control rod reactivity and global core characteristics are negligibly affected and~ local power peaking is bounded by the thermal hydraulic engineering factors for heat flux, hot channel heat input and LOCA engineering factor.
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'l United States Nuclear Regulatory Commission November 8,'1987
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Attention:
Page 2 FYR 87-117 i
1 C.
.Non-LOCA Safety Analyses i
All the non-LOCA safety analyses were evaluated for effects of fuel-pellet diameter tolerance variation.
Departure.from Nucleate
. Boiling (DNB) and centerline fuel melting are the primary failure mechanisms considered in non-LOCA safety analyses. The impact of the fuel pellet diameter variation on DNB performance is bounded by the engineering heat flux factor and the engineering factor on hot channel heat input assumed in our current licensing analysis. The impact of' potential fuel pellet diameter variations on linear heat rate and stored energy is likewise bounded by the engineering heat flux factor.
D.
LOCA Safety Analyses All LOCA safety analyses were also evaluated for the fuel pellet l
diameter tolerance variation. The tolerance variation primarily affects the certainty to which the' local Linear Heat Generation Rate (LHGR) and the local stored energy in the fuel rod can be predicted. The impact of the fuel. pellet diameter variation on local LHGR and stored energy in the fuel rod is bounded by the LOCA-I engineering factor.
In conclusion, the potential fuel pellet tolerance deviation is bounded 5
by' selected uncertainty factors and/or assumptions utilized in the Cycle 18 and Cycle 19 analyses.
We trust that this submittal is satisfactory, however, if you have any questioris please contact us.
Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY r
y G. Pa e, Jr Senior Projects Engineer
' Licensing GP/25.215 cc: USNRC Region I USNRC Resident Inspector YNPS i
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